Netport jobs that use connection pooling might result in constraint issues.
Depending on the data source, the netport JCL might reference a data set or other resource exclusively. Because a pooled netport connection can persist for some time after the data processing has finished, you might encounter concurrency issues. If you cannot change the netport JCL to reference resources nonexclusively, consider disabling connection pooling.
In particular, IMS netport jobs that use connection pooling might result in constraint issues. Because the program specification block (PSB) is scheduled for a longer period of time when netport connections are pooled, resource constraints can occur in the following cases:
A netport job on another port might try to read a separate database in the same PSB, but the scheduling limit is reached.
The netport runs as a DL/1 job, and you attempt to restart the database within the IMS/DC environment after the mapping finishes running. The database restart fails, because the database is still allocated to the netport DL/1 region.
Processing in a second mapping or a z/OS job flow relies on the database being available when the first mapping has finished running. If pooling is enabled, there is no guarantee that the database is available.
You might need to build a PSB that includes multiple IMS databases that the Data Integration Service accesses. In this case, resource constraint issues are more severe as netport jobs are pooled that tie up multiple IMS databases for long periods.
This requirement might apply because you can include up to ten NETPORT statements in a DBMOVER file. Also, PowerExchange data maps cannot include program communication block (PCB) and PSB values that PowerExchange can use dynamically.